A multi-objective grasshopper optimization algorithm (MOGOA) with an adaptive curve c(t) and the enhanced Levy fight strategy (CLMOGOA) was proposed to optimize the process parameters of rotary screen coating, setting the thickness and uniformity of the adhesive layer on the structural plates in spacecraft as its optimization objectives. The adaptive curve strikes a balance between global exploration and local development and accelerates the convergence speed. The enhanced Levy strategy helps the algorithm to escape local optimizations, increases the population diversity, and possesses dual searching capabilities. After multiple runs, the average values of the CLMOGOA’s reverse generation distance were 0.0288, 0.0233, and 0.1810 on the test sets, which were less than those of the MOGOA. The best Pareto-optimal front obtained by the CLMOGOA had a higher accuracy and better coverage compared to that of the MOGOA. Thus, it is indicated that the CLMOGOA managed to outperform the MOGOA on the test functions. In order to solve the optimization problem, 108 sets of process experiments were designed, and then the experimental data were used to train a Back Propagation Neural Network (BPNN), a Least Squares Support Vector Machine (LSSVM), and Random Forest (RF) to obtain the best prediction model for the process parameters. Considering the thickness and uniformity of the adhesive layer as the objectives, the improved algorithm was used to optimize the prediction model to obtain the optimal process parameters. The actual coating effect showed that the optimization algorithm improved the efficiency and qualification rate of the product.

This paper establishes a physical model for the non-contact rotary screen coating process based on a spacecraft structural plate and proposes a theoretical expression for the adhesive thickness of the non-contact rotary screen coating. The thickness of the adhesive is a critical factor influencing the quality of the optical solar reflector (OSR) adhesion. The thickness of the adhesive layer depends on the equivalent fluid height and the ratio of the fluid flow rate to the squeegee speed below the squeegee. When the screen and fluid remain constant, the fluid flow rate below the squeegee depends on the pressure at the tip of the squeegee. The pressure is also a function related to the deformation characteristics and speed of the squeegee. Based on the actual geometric shape of the wedge-shaped squeegee, the analytical expression for the vertical displacement of the squeegee is obtained as the actual boundary of the flow field. The analytical expression for the deformation angle of the squeegee is used to solve the contact length between the squeegee and the rotary screen. It reduces the calculation difficulty compared with the previous method. Based on the theory of rheology and fluid mechanics, the velocity distribution of the fluid under the squeegee and the expression of the dynamic pressure at the tip of the squeegee were obtained. The dynamic pressure at the tip of the squeegee is a key factor for the adhesive to pass through the rotary screen. According to the continuity equation of the fluid, the theoretical thickness expression of the non-contact rotary screen coating is obtained. The simulation and experimental results show that the variation trend of coating thickness with the influence of variables is consistent. Experimental and simulation errors compared to theoretical values are less than 5%, which proves the rationality of the theoretical expression of the non-contact rotary screen coating thickness under the condition of considering the actual squeegee deformation. The existence of differences proves that a small part of the colloid remains on the rotary screen during the colloid transfer process. The expression parameterizes the rotary screen coating model and provides a theoretical basis for the design of automatic coating equipment.